I also like the 'Now and Then' DJ spots but especially like the way the alien intentionally or accidentally intercepts radio transmission at the beginning of 'Calling Occupants'. Clever and funny. A very astute way to capture the attention of prospective teenage buyers / listeners - humour and sci-fi - on the promo video and if DJ's played the album version on radio. A good way to grab the interest of DJ's, too, to get the record played. It worked with some, by the sound of it....."Calling Occupants" gets my vote. I don't know if it's the better single, but it's definitely a more exciting recording than the flipside is. I'm not a fan of the LP version because of the whole DJ thing...which is strange because I never get tired of hearing the same guy (Tony Peluso) doing the DJ thing on the oldies medley from Now and Then.
On the whole, I've always liked the Klaatu version of the song better than the Carpenters'... which is another oddity for me, because in almost all cases, when Carpenters covered a song, I liked the Carpenters version the best -- but not on this song.
"Can't Smile Without You" is a good song too, but just doesn't have that special-ness about it like the best Carpenters singles do.